exhaust manifolds-with or without heat shields?

[69gmcc10]

I am looking hard for a set of Trailblazer exhaust manifolds for my swap and I can find them with out heat shields for $115 and will have them in my hand next week or there is a local guy that has a set with heat shields I think will be cheaper, but he is a pain in the but to track down (trying for a week).

Does anyone have any advice or experience on if I should even worry about heat shields and if they will make any significant difference in under hood temps. I am getting tired of of trying to track this guy down just for some tin covers that might or might not be worth it.

Advice?